Filter assemblies are used in conjunction with internal combustion engines to filter debris from fluids consumed by and/or circulated through the engines. For example, filter assemblies can be used to remove particles from fuel, lubricant, coolant, or air. Typical filter assemblies include a filtration medium encapsulated within a canister. The canister is threading engaged with a base, and a seal (e.g., a spiral-wound gasket, a rubber or silicon compression seal, etc.) is located between the base and the canister. The filtration medium, canister, and seal can be periodically replaced together as a single unit.
In some applications, filter assemblies are required to operate through extreme temperature swings without leaking and/or without allowing debris to pass to critical components of the associated engines. In gaseous-fueled engines, the fuel is kept at extremely low temperatures (e.g., about −160° C.). However, when a new filtration medium, canister, and seal are installed on an engine, they may be installed at room temperature (e.g., about 20° C.). Accordingly, after installation and once cryogenic fuel begins flowing through the new filtration medium, canister, and seal, these components can experience a temperature drop of about 180° C. (or more, depending on the temperature of the filter assembly during installation). While the filter assemblies may not leak when installed at room temperature, the subsequent temperature drop can cause parts of the canister, the base, and the seal to shrink and form gaps therebetween. These gaps could allow fluid to leak from the filter assemblies and/or debris to pass into the engine.
An alternative arrangement for coupling parts together for use in extreme temperature swings is disclosed in U.S. Pat. No. 5,628,517 of Jia that issued on May 13, 1997 (“the '517 patent”). In particular, the '517 patent discloses a cryogenic seal, which utilizes differences of thermal contraction of selected dissimilar materials to self-tighten as a temperature of fluid passing therethrough decreases from ambient. The cryogenic seal includes first and second coupling members to be coupled to each other, an o-ring spacer located between the first and second coupling members, and a nut that passes over ends of the first and second coupling members and encloses the o-ring spacer. As the nut is turned, the first and second coupling members are forced to sandwich the o-ring spacer therebetween and create a fluid-tight seal at ambient temperatures. The o-ring spacer and the nut have higher coefficients of thermal contraction than the first and second coupling members. With this arrangement, as cryogenic fluid passes through the first and second coupling members, the o-ring spacer and the nut shrink, forcing the o-ring spacer tighter against the first and second coupling members.
Although the cryogenic seal of the '517 patent may serve to improve sealing between two coupling members experiencing cryogenic temperatures, it may have limited application. In particular the cryogenic seal of the '517 patent may only be used in situations where access to the nut remains available after the two components are engaged with each other. Accordingly, the cryogenic seal may not be used to connect a filter canister to a base. In addition, the cryogenic seal may not be applicable to high-vibration situations, where movement and/or abrasion of the o-ring spacer could be problematic.
The filter assembly disclosed herein may be directed to mitigating or overcoming one or more of the possible drawbacks set forth above and/or other problems of the prior art.